Conventionally, a device that calculates a degradation state (State of Health, or SOH) in a storage battery, and, based on the calculated degradation state, determining whether the storage battery is normal or abnormal has been proposed (see PTL 1).
The device disclosed in PTL 1 stores a history of internal resistance values, degrees of charge, and temperatures in the storage battery, and, based on the history and the internal resistance values, calculates a degradation state of the storage battery.